Valved bladder prosthesis

ABSTRACT

A bladder prosthesis having a silicone bag with radiused lower corners and a band of anchoring fabric at the upper side, the fabric being densely looped to allow body tissue ingrowth to hold the artificial bladder in place. For entry of the urine into the bladder and emptying thereof, the bladder has in its lower part a valve communicating with a funnel-shaped conduit. The valve includes an adapter with fittings for connection to nephrostomic catheters, a valve body contained inside the adapter and having urine inlet and outlet openings and a deformable diaphragm-type elastic valve member to open and close the communication between the inside of the artificial bladder and the inside of the valve body.

BACKGROUND AND SUMMARY OF THE INVENTION

A number of procedures are known for the treatment of obstructivenephropathies, that is to say that type of condition that results inobstructed flow of use from the kidney to the outside, due to tumours orother causes.

These can be divided into surgical and interventional procedures. Theformer consist of forming an external aperture for the ureter, or forthe ureters in the case of bilateral obstruction, through a vast rangeof surgical procedures; either directly (cutaneous ureterostomy) or bymeans of variously used bowel loops. The latter, on the other hand, makeuse of catheters which, by different routes, can be insertedpercutaneously directly into the kidney (nephrostomic catheters),inducing drainage of the urine to the outside, or into the ureter(ureteral stent) passing through the stenotic area and re-establishingthe communication between the portion upstream and downstream of theobstruction, thus allowing urinary outflow. Nephrostomic catheters areconnected to urine collection bags worn on the outside of the patient'sbody that are emptied when they are fill. These bags are made of plasticmaterial, for example PVC, and are substantially rectangular in shape,with a tube for connection to the nephrostomic catheter and in somecases also an emptying tube.

Nephrostomic catheters have the drawback of requiring maintenance andmedication at the fixing point. Moreover, the fixing system throughsuturing to the skin or by self-anchoring means forming part of thecatheter, often loosens allowing the catheter to become dislodged.Moreover, the presence of the urine collection bag causes inconvenienceto the patient, besides causing a feeling of disability in patientsalready psychologically tried by a long illness.

Ureteral stents overcome the above problems but require that it bepossible to pass the obstruction, something which cannot always be done.

The aim of the present invention is to overcome the practical andpsychological drawbacks due to the need to wear an external urinecollection bag. A further aim is to provide a prosthesis that can beworn by the patient for a long time without problems.

Another aim is to allow the contents of the prosthesis to be emptiedeasily. Yet another aim is to provide a prosthesis many parts of whichcan be easily dismantled for cleaning and sterilisation and which allowseasy access to the other parts, for example to nephrostomic catheters,for cleaning.

Said drawbacks have been overcome by means of an assembly comprising abag element, at least one type of band material and a valve element.

The prosthesis herein described has been conceived to replace thenatural bladder in its role as a reservoir and in controlling dischargeof accumulated fluid.

The bladder prosthesis is made of strong elastic material, is shaped soas to be accommodated in the median hypogastric region, in asubcutaneous, prefascial site or pocket where it is positioned afterincising the skin along the subumbilical transiliac line and thenfreeing the integuments down to the suprapubic region.

The shape is roughly comparable to a rectangle with two corners, thosebelonging to one of the longer sides, strongly radiused.

This longer side forms the bottom part of the bladder whilst theopposite side is intended to be anchored to the muscle fascia initiallyby suturing and subsequently by incorporation into the reactive fibroustissue of a biocompatible material fixed to the bag for this purpose.The bladder is preferably a thin silicone bag obtained by spraying on amodel silicone material dispersed in solvent then evaporated, and thencuring in a high-temperature oven; or by dipping/brushing a modelinto/with silicone material dispersed in solvent.

The silicone bag could be obtained by whichever other known way apt forgenerating an opportune thickness of the biocompatible and elasticmaterial.

A silicone-metal-plastic structure is applied in the central part of thelower side, constituting the inlet and outlet valve of said bladder. Twolengths of silicone tube for connection with the ends of twonephrostomic catheters converge on this structure. Under the pressure ofthe fluid coming from the catheters, the valve opens so that the urinecan flow into the bladder. Emptying of the bladder takes place throughsaid valve.

This arrangement makes it possible to optimise the maximum size of thedischarge outlet and at the same time the minimum pressure for openingof the valve for filling.

Lastly a plug provided with a gasket ensures tight closure of thebladder throughout the day.

The valve that is described also serves to stop fluid pressure waves,pulsed or otherwise, from the bladder towards the kidneys. In fact anyreflux that might occur from the bladder to the kidneys through thenephrostomic catheters because of a defective valve seal would create apressure wave that would oppose the hydrostatic filtering pressure ofthe urine, and would therefore injure the kidneys structures capable tosecrete urine.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject of the invention and the inherent advantages will be cleareron reading the detailed description that follows of a non-limitingexemplary embodiment thereof with reference to the attached drawings inwhich:

FIG. 1 shows a front elevational view, on a reduced scale, of a bladderprosthesis according to the present invention;

FIG. 2 is a top view of the prosthesis in FIG. 1;

FIG. 3 is a side view of the bladder prosthesis, from the left in FIG.1;

FIG. 4 is an exploded perspective view, on an enlarged scale, of thevalve of the prosthesis according to the invention;

FIG. 5 is a section of the valve along a plane containing itslongitudinal axis; the entrances for the catheters are illustrated withtheir axes in said plane for clarity's sake, even if this is not afaithful representation; the valve is in the closed state, that is tosay closed to the outside but with access possible for the urine comingfrom the nephrostomic catheters; a device for opening and removing theplug is illustrated in section in the same figure;

FIG. 6 is a section of the valve along an axial plane like FIG. 5,illustrated when forced open for emptying, with the opening device andemptying channel applied.

DETAILED DESCRIPTION OF THE INVENTION

As can be seen, in FIGS. 1 and 3, a bladder prosthesis according to theinvention, indicated as a whole by reference number 10, comprises a bag12 made of flexible biocompatible material, with the bottom comers 11,13 rounded when viewed from the front, as can be observed in FIG. 1, anda rounded bottom edge 14, as can be observed in FIG. 3. A band ofbiocompatible fabric is applied to the upper sealed edge, with a loopedweave such as to promote ingrowth of body tissue in order to incorporateit. The band is indicated by reference number 16. Further portions ofbiocompatible anchoring fabric can be disposed on the surface of thebag, for example as on the areas indicated by 18 and 19 in the figures.A filing and emptying valve, indicated as a whole by reference number20, is applied in proximity to the lower edge of the bag and co-operateswith a funnel-shaped conduit 22. The bag is preferably made of thinsilicone, obtained by spraying silicone material dispersed in solvent,then evaporated, and is then cured in an oven at high temperature. Thebag, however, can be obtained in whichever other known way or in a waywithin the reach of a skilled person. A preferred material for the bagis a MEDICAL GRADE silicone. The measurements of the bag are preferably200×130×40 mm, with a proper wall thickness. The band 16 and bands 18and 19 if used are preferably made of a Dacron (Dupont de Nemourstrademark). Fabric woven in a special per se known manner to obtain asurface dense with loops of thread, within which tissue growth can takeplace for final stabilisation of the prosthesis.

The valve 20 will now be described in greater detail with reference toFIGS. 4, 5 and 6. It comprises an adapter 24, a positioning cylinder 26,a valve body 28, a mushroom-type open-close or shutter valve member 30,and a pusher element 32 guided by a transverse guide pin 34.

The adapter is an element made of flexible material shaped with athin-walled widened head, indicated by 36, applied in any per se knownmanner to the bottom wall of the bag 12, around an aperture in it (notshown). The adapter 24 further comprises a cylindrical part or couplingsleeve 38 into which connections or entrances 40 and 42 for nephrostomiccatheters open, said connections preferably being disposed so that theangle between them is slightly less than 180°. The nephrostomiccatheters are indicated with reference numbers 44, 46 and are made offlexible, biocompatible, tubular material Since said catheters are ofany per se known type, they will not be described in greater detail,here. Within the cylindrical part 38 of the adapter is contained therelatively rigid positioning cylinder 26, provided with holes 48, 50 inits skirt portion, said holes being in positions coinciding with theconnections 40, 42 for the catheters, in the adapter. The valve body 28is housed in an inner chamber defined by cylinder 26 and is closed tightagainst said cylinder 26 by means of two O-rings, indicated respectivelyby 52, 54, accommodated in seats on the outer surface of the valve body,on opposite sides with respect to the openings 48, 50. The valve bodyhas an end chamber or chamber for the open-close valve member, indicatedby 56, and a valve chamber or pusher chamber, indicated by 58, betweenwhich chambers extends a perforated portion or septum 60. The chamber 56for the valve-member is defined by a cylindrical outer wall 61 withperipheral openings 62. The pusher chamber 58 has inlet openings 64, 66in register with the connections 40, 42 for the catheters in theadapter. Partition 60 has a central opening 65 and side openings 67. Thevalve body also has further through openings 68, 68 and 70, 70 with axesat right angles to each other. The openings 68, 68 accommodate the endsof the pusher guide pin 34, whilst the openings 70 accommodate plugs 72,72, the function of which will be described below. An end part of thevalve body is shaped with a screw thread 74 or other engaging means, toreleasably engage a cap or cap 80 (shown in FIG. 5) which closes thechamber 58 with a tight seal by means of a gasket 81.

The valve body accommodates a stem of valve member 30 in the opening 65.Said valve member is mushroom-shaped with a stem 83 having a bulge 84 inan intermediate position and an enlarged cap or diaphragm portion 86,said cap preferably having a frusto-conical or tapered shape, with anedge or lip 87 having an external diameter sufficient to completelycover openings 67. Member 30 is inserted into opening 65 so that a partof its stem remains inside it with the bulge 84 on one side of partition60 and the tapered widened partition 86 on the other side. The valvebody also accommodates the pusher 32, which is substantially cylindricalin shape with two diametrically opposed operating protrusions 88, 88,spaced from each other and sized as to be able to pass through openings67 of the partition, 60, and also has opposed guide grooves 90, 90,substantially of the same or a slightly greater width than the diameterof guide pin 34 and engaged on it, so that the pusher can slide axiallywith respect to the valve body, and be guided by said pin arrangedtransversally therein. The pusher has elastic return cords 96, tied tothe valve body by means of the above-mentioned plugs 72, 72. The guidepin is preferably mounted on the valve body by means of cylindricalgaskets 35 or with end plugs 35' and a retaining ring 98 is arrangedaround the ends of said pin and the plugs.

According to the invention a valve opening device is also provided,comprising a cap unscrewing element and a pushing element to open thevalve member, said elements preferably being interchangeable on a handlehaving a channel that can also serve as an emptying channel. Thisaccessory device is shown in FIGS. 5 and 6 in sectional view along theaxis of the emptying channel element, and will be, described below. Thedevice thus comprises an emptying channel and handle element conduit,indicated by 100, a locking ring 102, a cap engaging element 104 and apushing and discharge element 106 for the pusher (FIG. 6). The capengaging element has a shank 107 that can be engaged in the conduit 100,a cup-shaped part 108 and a projection 110 designed to be engaged in aradial groove or hollow 111 on the bottom of cap 80. It will be seenthat by arranging the cup-shaped part 108 around cap 80 so thatprojection 110 engages the hollow 111 and turning the conduct 100 whichis accessible from the outside, it is possible to unscrew cap 80. Oncecap 80 has been unscrewed, it is possible to apply pushing and dischargeelement 106 to element conduit 100, said pushing and discharge element106 comprising an attachment shank 112, a cup-shaped part 114 that canbe screwed onto the thread of the valve body, and an inner cylindricalpushing part 116, all these parts defining a through channel 118.

The operation of the prosthesis will now be described.

The urine coming from the kidneys is conveyed inside the valve body 28through the nephrostomic catheters 44, 46.

Here the fluid could take two different opposite routes, but one, theone communicating with the outside, is functionally sealed, at thisstage, by the suitably tightened, threaded cap 80.

The second route is towards the reservoir or bladder bag 12, to reach ithas to pass through the valve lumen proper, formed by openings 65, 67.The silicone valve member 30 presses on the edges of the valve bodypartition with the retaining lip 87, creating a tight seal against thepassage of fluids up to a certain head pressure. The diaphragm 86 isheld elastically in a closed position by means of a force inherent inthe shape and material of valve member 30 and/or imparted by an elasticelement (for example a thin cable--not shown) which exerts its force,preferably adjustable, parallel to the valve axis.

When the force due to the pressure exerted on the undersurface of thevalve diaphragm by the urine coming from the catheters exceeds the forcedue to the elasticity of the materials, the fluid enters the bladder andbegins to fill it.

This mechanism operates whether the patient remains in an upright or asupine position.

Obviously, the pressure within the bladder increases as the bladderfills, putting up an increasing resistance to entry of the fluid.

Once the bladder is full the pressure of the fluid from the catheterswill no longer be sufficient to overcome the resistance of the valvemember and the inflow of urine will therefore stop.

To completely empty the prosthesis bag, it is sufficient to unscrew theplug 80. As soon as this is removed there is a slight limited dischargeof fluid. This small amount is that always present in the valve body,coming directly from the catheters.

With the bladder bag completely or partially filled, its internalpressure is greater than the external pressure (which coincides withthat of the valve body) therefore the mushroom-shaped diaphragmcontinues to adhere firmly to the passage section.

In order to remove said diaphragm from its perfectly sealed position,the pushing and discharge element 106 with the handle conduit 100 isscrewed onto the valve body.

This connection raises the pusher element 32 which thus raises themushroom-shaped diaphragm with the points 88 (FIG. 6), allowing thefluid in the bag 12 to pass through valve 20 to the conduit 100 and tothe outside.

If, before emptying is complete, the connection is removed (byunscrewing it), the system of unbalanced pressures immediatelyre-establishes the tight seal of the bladder, interrupting the flow. Theemptying operation nevertheless ends regularly when there is no fluid inthe bladder.

Removal of the pushing and discharge element 106 in any case causes thereturn of the diaphragm to the position in which the filling-emptyinglumen is sealed, the diaphragm being returned to that position byelastic force, and the return of the pusher to the situation in FIG. 5,because of the elastic cords 96.

Once emptying has been carried out the screw plug is again fitted.

The funnel-shaped conduit that serves to prevent emptying in unwanteddirections can be cleaned, dried, washed and lastly folded beneath theclothes.

It will be appreciated that the valve body with the pusher andattachments can easily be periodically removed for cleaning. With thevalve body removed the catheters can also be accessed for cleaning witha swab and/or cleaning fluid can be introduced into the bag.

We claim:
 1. A bladder prosthesis assembly for subcutaneousimplantation, comprising a bag element made of biocompatible material;atleast one band of material on said bag element suitable for facilitatingfixing to body tissue; a valve element for inlet/outlet of urine to/fromthe bag element, said valve element being connected at a lower part ofthe bag element around an open therein and comprising connections fornephrostomic catheters, wherein the valve element comprises an adapterhaving a coupling sleeve with said connections for nephrostomiccatheters, a valve body at least partially disposed in the adapter, witha tight seal, the valve body having openings in register with saidcatheter connections on the adapter, a first chamber communicating withsaid openings and delimited from the bag element by a perforatedpartition having a passage therethrough, a valve member being providedon the valve body and moveable between a condition in which a peripherallip of the valve member thereof seals the passage through the partition,and a condition in which it leaves said passage free, and a removableplug or cap to close said valve body with a tight seal at an end thereofopposite to the partition.
 2. A bladder prosthesis assembly according toclaim 1 wherein it comprises one said band in a position along an upperedge of the bag and further band portions of said material on the bag.3. A bladder prosthesis assembly according to claim 1 wherein the bag ismade of strong, flexible, elastic material and the at least one band ofmaterial is made of material suitable to promote tissue growth in orderto fix the bladder prosthesis assembly firmly.
 4. A bladder prosthesisassembly according to claim 1, wherein the valve body further comprisesa second chamber separated from the first chamber by the perforatedpartition.
 5. A bladder prosthesis assembly according to claim 4,further comprising a pusher element in said valve chamber, said pusherelement being axially moveable in the valve chamber between a retractedposition, in which it does not act on the diaphragm-type valve member,and an extended position, in which it acts with points thereof on thevalve member through at least one opening in the partition, said pusherbeing elastically returned to the retracted or resting position.
 6. Abladder prosthesis assembly according to claim 5, wherein said pusher isengaged with a transversal guide element in the valve body, to guide themovement between the retracted and extended position.
 7. A bladderprosthesis assembly according to claim 5, further comprising an elasticmeans connected to the diaphragm-type valve member to return it to theclosed position.
 8. A bladder prosthesis assembly according to claim 5further comprising a pushing and discharge element, said elementcomprising a sleeve or cylindrical pushing part of a suitable size to beaccommodated in the valve body and extending axially sufficiently topush the pusher element against the diaphragm to open passages in thevalve body partition, and comprising a through channel, and in that itfurther comprises a handle-and-channel element connectable to saidpushing-and-discharge element, for allowing fluid to pass.
 9. A bladderprosthesis assembly according to claim 1 wherein said valve membercomprises an attachment stem and a mushroom-shaped diaphragm made ofelastic material, said valve member being essentially undeformed in theclosed condition, whilst in said open condition it is substantiallyelastically deformed.
 10. A bladder prosthesis assembly according toclaim 1, further comprising a device to unscrew said cap, said devicecomprising a handle and a cap engaging element, removably attached tosaid handle.
 11. A bladder prosthesis assembly according to claim 1,further comprising a funnel-shaped conduit located on the valve element.